Shallow (1-5m) coastal lagoons are a common feature of Alaska's arctic coast. The waters are brackish (20-25%) in summer due to runoff from the numerous small rivers and have temperatures in excess of 8 degree C. By September, runoff has ceased and cold (O degree C), saline (30%) arctic ocean water begins to freeze in the lagoons. By early November, ice is 50 cm thick with salinities of 32-34% and temperatures at the freezing point. Salinities increase at a rate of 0.04% per day due to the brine rejection of ice formation. Currents are sluggish ( similar to 1 cm/sec.) and show a seaward transport of brine. By April, ice is about 2 m thick for most of the lagoon frozen to the bottom. Salinities in deep parts can exceed 100%. In early June, river channels and lagoons are flushed with fresh water in a few hours and remain brackish until the coastal ice breaks up in July. In the open water season currents are wind-driven and waters are generally well mixed in lagoons. Prevailing winds from the north-east produce westward flowing currents at 3% of the wind speed.